1. Technical Field
The embodiments disclosed herein generally relate to telecommunication networks, and, more particularly, to providing call forwarding services based on Session Description Protocol (SDP) attributes.
2. Description of the Related Art
The recent advances in telecommunications technology provide a wide array of special telecommunication services to subscribers. The services include basic call setup, enhanced call services such as call forwarding, call screening, geographic call routing, flexible call routing, calling party name/number display, three-way calling, accounting and billing, flexible carrier selection and the like. To enable advanced telecommunication services, telecommunications networks generally carry signals as well as the voice or data comprising the conversation between the calling party and the called party.
In telecommunications networks, call forwarding (CF) functionality allows users to forward incoming calls to an alternate number of user's selection when the status of the called end is busy line, or no reply, or unconditional call forwarding and so on. In general, call forwarding process involves accessing a database, retrieving call forwarding information from the database and using the retrieved call forwarding information to forward the call to the desired final destination. In first and second generation wireless system, the number of successive times a call can be forwarded is limited to avoid overloading of the network due to bandwidth constraints. The third generation wireless systems support higher bandwidth access by arranging more complex processing in network elements, so that it provides multimedia, new value-added services and use new interfaces.
IP Multimedia Subsystem (IMS) uses the advantage of IP networks to provide traditional supplementary services, such as call forwarding, conferencing, and call waiting for subscribers on an IMS platform. IMS defines the standard Session Initiation Protocol (SIP) interface between application servers; the IMS core network Call Session Control Function (CSCF), and the IMS subscriber. The interface between CSCF and the database, the Home Subscriber Server (HSS), and between an AS and HSS is based on the DIAMETER protocol. There are a number of call forwarding services such as call forwarding on busy, call forwarding on no reply, call forwarding unconditional, selective call forwarding and so on in both traditional networks like Public Switched Telephone Network (PSTN)/Public Land Mobile Network (PLMN); and new age networks like Next Generation Network (NGN) and SIP based networks. Also, many new data services, such as instant messaging, video calls, video on wait, and web-based services, are also be available for the IMS subscribers.
However, the call forwarding services in case of IMS subscribers in use today may be based on called subscriber's line status and calling subscriber's identity. The current methods provides no call forwarding services for IMS/SIP user's based on media attributes, network based evaluation of SDP or partial call forwarding. Furthermore, there is no call forwarding based on session attributes, such as, whether the call is an audio or video call, the call is of low bandwidth or high bandwidth, or a certain codec type is supported/available or not by the device. For instance, if the called user is in a visited network where high bandwidth calls may not be advisable due to cost, QoS or the like, possible to forward the calls to a Multimedia platform. Further, if the user have a hand-held device that supports only certain type of RTP streams, then for example, forwarding video calls to the house would be convenient.